SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e70cc1490d158973e423c0bb54936856fa693d017133b269fcb6a6d9f3f340f' 
  AND token = 'spL1YhTHH+A9ecdyRLFzDP4Jkl/3qUvOXnJRgL9ksEQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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