SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'a8baabcbc664c6d94a621e7d4191eaf3d8d50b5c8db1e8d166086aa80c958620' 
  AND token = 'os3AqB2f4ntUx81jzPPXNnxk005biH03HBdEFVa2fyc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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