SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03378a7eefb223a0ccee15f2e3eb41e629a7562618fb69db91c8e1d06740cf4d' 
  AND token = 'xG2CpIsqmJrkK/zjlI5AikKCuPjnm50N1ztLwVPTFgY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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