SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '409a2ac6c03256ec1e591dffe7dfe47ceb0ad4bf754c450206356cf3b9846a5e' 
  AND token = 'JTq1JrpVp8zyq/Kkv+P/MVtwGhfRTjRusYH/iKKERAg=' 
  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"
    }
  }
}