SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5aa3df3e7838f487645f264e084f8449aaebe90a4fb096dddc75eb3a7fdd096' 
  AND token = 'FT6RAGbhSSAq9B2cQryJB7sxgweWW1JwjxbJsj34ks4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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