SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '17841e59f55818485d2202eeeb1daae41bf55a0440f47724cef66da74be2fda9' 
  AND token = 'gJEe3YuSGPNrmOgYaP9jYSACYInUiAJ/fiDWX8IOMFg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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