SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f02ab5cc6c0c5a5198fc75356f5d3bf60f5e5b05675d0eef562f0336f894ea45' 
  AND token = 'fxiiMrPdltrb/d9jNiwwZhI+mk7VKPK80FsZhmCfB5A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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