SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14128d2b668027f1ddf1731f24637b3e5af8cc47a1878688b3c68a7f6ee7cb6b' 
  AND token = 'yUsr5OlTGzVyEMCqmmm2Wx7MMS0v45ApWYAz2ww4ANE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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