SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e868ab6b8fb960c781978156ab05515c69f03916a7ff0916a29eb42ff253064d' 
  AND token = 'hDkT2RcdLahs7/rez1IjGzuggXMU+sTK2DlS8sufCiE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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