SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4b636812198007f04b1b9b9535236aa113bd6ef1cd60623a7fab9d45f5a07fb' 
  AND token = 'hR6Mt+bMz83TvgbTDCGx1gR4IThShmqMzTg8rfUfqaA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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