SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '364e552ba42caad99359631cbcdd647eba686f975ad6d64dcd709df685db0c53' 
  AND token = 'WEBY1Gg+IY0/Uqv0lsAqwsD3TANKcQ5bEVSODu42cbM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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