SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4e205cecc62f6af35f65063686c4c027d8b195ca0e892641ad9ffa5cd3aedd9' 
  AND token = 'mu1Ajz9+nKIowXjAJtKLMxzWbbXiHEdKl7B2/wN0XLU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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