SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f87a927a1a13ebc5ed3887d32afb0c32649970f52f10426f93ef9adf55982f6b' 
  AND token = 'Cjr1uFBN3dnGMpMK/0lMl6+8es48FQ05GHvAxhwXM+8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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