SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38349033633fab45a8801b8c89d18a9bdc799cbbd4870eea2c7d426d96af2eaf' 
  AND token = 'w3mqzyMHjPsJ9viqX6wWOhBahIDdq7DnCpltqxEHwRo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}