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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e2833eea5a9a1596dd7a4b3505e214cd51df37d7a8d09ea7057b258b3d7cf3a' 
  AND token = 'RjPRIiQ9USYJ91xMMJ/1Z7SqAozxK3GpsKFDHlD6fOo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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