SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87a1503a68521696c9b1c01cb954587cb5aa0046e82aaeb1333c4391543f2b4c' 
  AND token = 'OhjvwGIufCtOkzOJoVgR8Mz1uwJD2OL7/JYifTAtSBs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}