SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '263301fcee09d8456c81b0dbf992f16bff02b8f7845a48aea06b084f678fc3d1' 
  AND token = 'NB4/l0hB9Zjb2s+vfkLv/B6wEKtDAwzXsEc70oZGDcU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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