SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '26536663a8ceaf37532c81562a498033361804e8288933e7c596fcb3e03523dc' 
  AND token = 'aFfRxQNuUWNgcRukxu2RXZKqkXQ0j4bpkUhDuYuM+a0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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