SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '91e88c31b37542997f6adef5db1fc67dbf106ec47a0d5b9bbff1ea4238d5e29a' 
  AND token = 'KasGD5P7+KYRvtvAU/QOUDjG+lae18ML2YMwc1sOwEQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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