SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a219e3846f598fe8feddc1a01815f70c55f9617bf6491ac502b032faa9e1f9fe' 
  AND token = 'P5XZNhpTYXE2WZJTysx8ioJRTaRgg5pXUTJBjmlrNMY=' 
  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"
    }
  }
}