SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '545b95e0071e303c636a56b2da126a6b718c52a11ae2201d18da63e7eebc72e8' 
  AND token = 'Dj89Q8WPeiWTvdR+KAlQ60LBPvHIv0SkPmtofFUVm1Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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