SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a40fdf5977bc800086d574183b0fbadc2bd2ea0c0ef8cefe991ac83a99729143' 
  AND token = 'QF0EAe25V7sh7KC25h1tGr29yvNj2dhq72qX6imPeiM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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