SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03e47b6fe9d5d8e76ce6ad17988b7557bfbc42cd85f95f91418a2a929726c938' 
  AND token = 'Ll2dwJ3hSGur91+bdGLyKnEMYgJFPRoGT18/DbDHoBI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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