SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31d38b2a3fc23a2a84d3864ad66790cfcb4120cfe3295d4cb06640d4d9de494c' 
  AND token = 'WvOxRnOI9y8zClbzj0mHZPF8irxjagbNh/zd+pTSX7c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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