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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '852c28fabf228369a5869c72efcfed53b2de352f185b8319cd8bb47aa062c656' 
  AND token = 'MmWNO/SO63t7Ha79BB5InF1I6MeDz7ydxot9AMh7kFc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}