SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '254e6f6f29dfaf9c07c0baa8cc93478ff1fe31538dfb91f67897e3452924d5bd' 
  AND token = 'n3JZ+aKb1bgUzRYYL3CV+G8uUEh2qYU6k0RbdgES3tI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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