SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2be842a797782c316da1393258ca4831a30205b35babafa7179372443f1401cf' 
  AND token = 'Ns/CVYwDNE2xRwmCwtl+HRghgHY4LkID8kWYPNQ7aFw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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