SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '714a56b32efc214daa972a91ee8b9aa45916a46f23f7a2221035da2dc66e7548' 
  AND token = 'fBl6TCJAUNb/wVYEp+WTm1DMs8cbf9H1uBaYx/xbbw4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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