SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6bd92349bccd7d2c53fb2f219f30ce2cd8b1a70d8f6aad825d9fa82263385043' 
  AND token = '7HwaQ2K7tgnYCfIB9+YdsM2XllrXQr2DqZbDHXanG/0=' 
  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"
    }
  }
}