SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a383ee506d49c55d31baedc974c43d4a0a2bbd2e050694122a454c1e291ee5b6' 
  AND token = 'xTAMpQcOHjluevopEctXsZZ40qghmCk0jEMjSDnIivo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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