SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '21cab027d4161a0ed6563db471087438d2cd3ce7c30cd73cee034f99757e59db' 
  AND token = 'i10n/kMwwlGJvQqbFg//45rBEGgOUq2XEFZWahLTWN8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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