SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3404610cf5c3f7f3744cce273e01d664f33f1c1a5c20c4ae345849882fd4a9db' 
  AND token = 'yBmLydgOm3YTo9mfbA6HaktaRqLUoQZGXi5ZvfmRHhg=' 
  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"
    }
  }
}