SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '1c1f87e720c46493c95fb0547f6e853e1185a992e45594cb70a218164b15b214' 
  AND token = '/MdyNSuXhdEBO8wkTrXqqplqq9HWkAipcGEhHrqMaVE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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