SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1afc377b5b45d7470ea5a0f4ff44f163a296153589b260168d471f4bf0b3d2c5' 
  AND token = 'uGXTwZ0VET8dMAdjLGJOTRMUpAmVD3B0YgCi02+pYGI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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