SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8358a68d8c2cbd89e937b0df82adac6965de1558669d537c0af2a48dca2a4910' 
  AND token = 'YPPv8UaqgZFkWRwX8U2JkxeSO8zN9vjqqgbHdvjqUaE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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