SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '578364798835c3596baaa5ea799738659552c13decef17d9c03765b1a66b2b90' 
  AND token = 'b7eB0y79K9lDfArpLK6uu/r1KCt3RD6SMpE0DOrhVSc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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