SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a792eef84b6e8d0630d36b2e8590412fe1441a57cbf0746f81940fbb37a6c01d' 
  AND token = 'fOwSRGPZdqV10zXwDnjN0uPGc2XXDzbT+9/FGMSQYkU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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