SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '536d302eed025782cfca04499392d055a15c309a6746532b68eb5b57ab8384a6' 
  AND token = 'ol62ZrNAM81psnPCN1xCMOAWEyS49m3YoOsmX36Ddr8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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