SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'e73b155f9285a5917f929d5a5899819e2b3f9d9f2301150dee167988b435454f' 
  AND token = '6edSLHGJFMyBLqJrdpQVC6ba8RTZJuCkSNwkcwTz4+4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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