SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7268c2915afc873a367e77038cf47311fa3263c251df75bb6cb7b3a8c22444f' 
  AND token = 'bmerPO9MZ7Rl6VwLJxOBtbabH1kmBbJdDm54RMuA34Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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