SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9bb16a0722449841ca4e445922c2b6da7b866a8b0ce85d78c6754f5c5ec3012' 
  AND token = 'gKpbesFXDHW928MJNWyWLq68kgHM2iiJNbcA19WcUOA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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