SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3f1fe7d22ee7dd443a1bee57fafdacc42bae0c7d282e29010b21341e0f1c55b4' 
  AND token = 'hL4nXnQuUzhHa5TLfQH+N8d9ljtcZhdVqS4K7bVQn/4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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