SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84c8d464ba1cd06a8a6ed0b4446a98ba46fde66e607459d26f358f25b09fe012' 
  AND token = 'rNGKlYl1+VUz1x6fZiLzphH2hYgNuPJdriLEfNNW2zk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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