SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39704b5698c87fee55c3493146b64b9bca6dbad98f43b1340c715f740eaf4522' 
  AND token = 'u49G3/hU8QOKyzZQLqFyzvAfhD7hdywHe2O+OU/xeAM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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