SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a56077ef6c89ce7f550630764f8846438740e953a710d760a2a1d55ef4eab98a' 
  AND token = 'l4nQrkbxqyhQGeqxRfKkeOWQlOQCiDlzRK8nUwpQBps=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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