SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '893bffdecd65b02a7c24638ca85d2feea2e28940190997a92fe046c19d8d7153' 
  AND token = 'xDSlmpxVfRPOq03+yvDMRwmo2wJ20QkVZvzZBigS55A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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