SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '4221a22125ff833e85fa89d6792097754b2cd31f4e94d91a5bf7eb5c9ae31824' 
  AND token = 'MAf9zgwiRTWZe9O/cPrF+cY+3UW+EVlgjGBXJ/VdYDI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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