SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bbb529b2fafbef7705cde4e2b9708861e42668c98d463990581148e9115f0334' 
  AND token = 'AmH6WSAF4PvfzkHjkFFw+iKBYmH2PWqGRdikaadODBk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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