SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df403fd9366b979fe60a1aefb6bade9cfa9dcdb73efa8460691bd863cbeb034a' 
  AND token = 'aSVigb6sBiQDw8y9VvZnVIqlDP4ltMe32DiufVADdug=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00082

JSON explain

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