SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3136fad543b33c94540706e9c824d2f59f0a34bacce8f3e8793ac98bdbfb8e72' 
  AND token = 'bNI8lYDjo0TafwrbtwO77m9fJX7+flBH+MAicR2esdc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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