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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c47ce9814dc3be74ec3ef4923cd8c5cbcd43412f1e76cf6e8aa42575468d54b1' 
  AND token = 'NsWMSpt/j2HElPD8ppqTiSeOw97Z2BlTS7/7s08hiGM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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