SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '25ca96ec5c1925d46853f2fcf4a15b002d2901f1b070f9743346337153792799' 
  AND token = 'Pvd+BSGxf9j7CpmFlvYtTWUftxXMpRXmDP//C27hERA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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