SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b082733c7a603826a838d27c57940138c0df7d8e7ce1ab4bdde3b41878b8dfe' 
  AND token = 'HcL9LT5sOkuxCviR5t2DhEl30cCGRk2gg6NZCIlsxzI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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