SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3921e753a056f05061fb17c9fa82ad973dced613a1eabbaf401f427efb3415b' 
  AND token = 'XCFunZ9mxu9dv38116PcCwZAmtA5ts3cGlt42WnMQIc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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