SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b35bea3ae7b5fba7f73b0d2cff964f8e745017a7bd417f326050da00e8297b14' 
  AND token = 'Sw1iWqC1a+TPhyJoz5mqxPPngo80bODfzKW/Lc80TS0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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