SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b5c1b77179aad23efc4d67b07821ad47caaaa7b13c5d377a678cdefeca5fcec' 
  AND token = 'TvPK8ku1H217mi/LZloxTKGhrYzpqUF16reqMgDakBM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00010

JSON explain

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