SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31491c812d57deb1fa8e590c20bcdc66259e5a2d7366c956fdca2511307c204a' 
  AND token = 'JSpkTD4CAWyscxo+wPAuYeXTBaVRuxKuFI+gKCNJQiE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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