SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '438f0a8799a78908d6a9fab62a3e098403ccc101f3ad09b3697f108fdcd635ca' 
  AND token = 'Hnf2zvG3STxRp/sEYIV2jA95jKwIdGm4tgvGJp4YpBM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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