SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '426cb0d21ca6edc73c80dde6de0365fd7f0cdf31aa9f89d8de7866cbdf336b51' 
  AND token = 'XlJwkLFUwGMQ4IZ8t6LjVSpC4sW/XG98HL2YgOqXuns=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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