SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0fefe26716c3023fba8fb7f2d992210cc206cace5aaaf43713947a9f03e889bc' 
  AND token = 'JkeZt5pdH5gtA377EHGKawmc4htgN5L8e5jnUY0ToEw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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