SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0ace9e23f0afbe52903093edeb713bced7da2d2786b2b41f06ac34d4584aa86' 
  AND token = 'hdjZvW2CsnqQ6h2GgbDIMoo8ECf0h4Mzu/RbM2SJsZg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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