SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5db6d477e89a35a8e78e10fe7671879336a5040a412f5bf69407b97930dbc5c' 
  AND token = 'csUtE8p21tLBGH+8CylxjjJG+SJukycccmTZFzhah8w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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