SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7296c31a64cd8dd66922d3f506feaab3ef756beb04c9c39f996d690f315fbdc' 
  AND token = 'yA7mexRIhCSk7+UMMcabQDpqs55ZYvkRFCrEFbYSock=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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