SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5bdb4cf0586e6aa948775af83c07d39791d86803f341fa975e2715bc64494e0' 
  AND token = 'B/rcHtlX9wb7zHGraQNgFvqNRYlQKzDEENYcNS+yFjQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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