SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1ffda42329fca5770149fb17c584c486edf7afe3a672daaec9aa667a3714b94d' 
  AND token = 'XXS8xNPCL1nsKen1XZRLMdfdTc+MkiAHPFqTx5BCJpg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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