SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ebee6b3575e38cf7fc8bceed5e52f4bc685f8e18197edcff7c57fe1fdbd03be1' 
  AND token = 'M69//LyknHVv9bBZNogLwJLkisgsyFh1e+UykT+uurw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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