SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d5bb4fa67470325bb9df32035e8d64b945526838ba1c339a1776988f0220842' 
  AND token = 'Mtng4WB36ZkFUHDQi7GVPTRFK/8kUVG2Ia9FJY2NTBQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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