SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '90cc6bc83d86ca63fc664c12f63edfa8107d6c3c35a366094251cd85fed985fe' 
  AND token = '+J3lK7tBWVO0uppBmjrgfOFwvb0YjExMx2cBKZMmzy4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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