SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '718936a2fdf6e2cc801cd022d3ba3b8e96f89e042976e86f81fc9ae12a6c6fae' 
  AND token = 'vgY+OQhSKwwG+/rA5N8DgAJIAuZ0zh5FufsT6G6BvjI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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