SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'd86aa57400563e2d947bdaccf1251327cb75f6777503ffe665ed414400c8779e' 
  AND token = 'jidHq+oSYKFn2d397rOnhA5pREDDsbTx2pWTHosKkwc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00062

JSON explain

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