SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cdf34c1df2689423f8f3cbf795847b742f5845fedd8709820d46fc01a2efccdb' 
  AND token = 'Avxvyhu5+2K74gQseavhhsQbqxf+lVTvmlv8QfPZQsg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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