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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f72a2d9e7eee33f91a3f00cc1b85a5eb68ce9226fb399b8dbf6fa46ddba8c345' 
  AND token = 'KW3zl1gXx1uOKZV+RA3TyZLktvFMeVt55DiXdZBMtTo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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