SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0f0a71e69f93e1de4c341cea5b3babea9dc88d70d60c139da05830a081370e3' 
  AND token = 'U8tXJtnC4S707Ux0xFSoPQFEU2GoTrzAlbJKwpziTRc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}