SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f5f5853edc388966ca937fcb53532472884a031e720a6816ac21aa1021c89e7' 
  AND token = 'Jkfxjala+Uakne7nZT8bZIWas9M6uaxZ7NkTRv1nvmM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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