SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5620f47bb93e1a9ed4ff3f7a36a31c51620c857341b112d6e7ab0965db3b6548' 
  AND token = 'wsfHfsHGx1JPw/mYZfnsQcK13PrOJezYlr5crjtzWHQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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