SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8fa31d10593d0c12b945b578716725a73def6743c415f8c2fb8cd64971a2085b' 
  AND token = 'wTOXOw55SBwP7CSR6DmOVCKB7gtn9YjDhvtsO3+c67c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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