SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7221d0c9053d8ec8986de6b6968365bea5ce673a93d42c47e4b7db991cc0b44' 
  AND token = '/akKlpxw9vAA33+FLGIjJXkw7AzG/nVyujqQyNy84aA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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