SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82a5dc30e010128d839d00266d3d9e330c012cfa71b48385307259cb77d2f7b1' 
  AND token = 'm++HAQZVszxYPwWee3+prss468mddzK3mZqwVDFjxAU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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