SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef260a681cc0a9a3f6a30e1ed0d6281fd2111e79a4b9cb100e4210517c55d91f' 
  AND token = '02AueNdFdsRvhZKqYGTLaqYJ7K0+nRdfxnstXzcrAhE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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