SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a242ebea8f8e4629dcd0af820cd386065494c3123054139ab7b7c54a41be46ff' 
  AND token = 'Rq+Z7PDYGjoXbRMiv6tOzyPGEoHOya21Y3KsVEBYDPM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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