SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5bfa1fa6f79043c05d959baf790f10533eae94c1e9ccab7de375faf9a96197a4' 
  AND token = '8wRqRWlBFdVSTBCGDz4QaSsVPuUJd5wrg9Py5YEcKKo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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