SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75a1577f9071903d9e316c3ffaa64f0e76b98d1e286c87b2d2143f94f0ca3f25' 
  AND token = 'WC+4YIuhaiwR/SRP09hZf8HrNAfaDlUuTndKqz6VFd0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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