SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '25edc2900e08efb762bce991e44568bdf286af35f8ad006494b2877d4052f101' 
  AND token = 'F8xBd3MMlsgCfRJs3dhfQCfJunXtD0Wph5/EDVU0VfU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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