SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a26f70f2382be088e1c1f5e1508a501dc6fdfacf1ff14e54343c1ce5c0d536a2' 
  AND token = 'IiUbBAnhpayIdD4/hNG7ZfixmJOXZ12TtoHcOulNfNc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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