SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46154b027315902e11056b5ab5572ccb53be004f60f10274041a2c96c4d45c14' 
  AND token = 'nfV7xt+IK0kL5UG/OOUGydGNc/Ir8QgyFMuvjl+yg4I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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