SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '585d0e3d325251c9c3ad41bf75c898e299ecd407a27db43245dd775f82c37d31' 
  AND token = 'LqTDacH8f4p8GmWLVxVNeAHVBE0ndDBk9IfuaVoqKOY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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