SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c818c343d22de68e01e2d61296e7f9f8a2eeda2ce896429bf8f1035053e6c25b' 
  AND token = 'VQM2k1tunDJK6MHfckaC3/4W+oYX9WCfcs56Yu2E4Cg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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