SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19a57665d7f2e76df07f54435512141dc4bc65f8f0788b04ebb0ad476f95650c' 
  AND token = 'Jh2mpzHTPego+0eH+N/qnTZJQ/qTjB7jl1TaO+KYZLo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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