SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'd0ebdeb6e998300b3c1f0a3be193fa67db5d3ab58fac5ddea302f0d4d533af53' 
  AND token = 's7DmoxkZ+5IMj10GiK/ddyAajJ06dofu1TpV1Xvv0W0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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