SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e16e4db44f987785608bcb612da8e91e048480d9c2366a842a794fb8e52d4424' 
  AND token = 'Vt3zJmosolBiZyHU/KduXQjCCgDbz8PNCJXTBygTaUw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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