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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f7ea89fe841a1a58e80f0e76b5e538643aace624a11a3e67e5b6b08e1f205d2' 
  AND token = 'tx0AKKrHOBEcFFVGC+4CSCs0LcW6YkYZ5rQdwR9u+c8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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