SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ccb00a00c7ab2bb1efa9bb05d86a102ec86e649e97ab468c50b86f6dad1a6331' 
  AND token = 'tyMF5VknRUFr15cvXvDpdm8mbCXEvpK+z3ZDVCD8xOk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}