SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e63b7263bd1dea97e41790f48778dcdfff912a16c0e0e37f345705d6448d3b87' 
  AND token = '8CUf6QcpxjdYzjLPGOghlFXXXrUw99HxQ4f4SUmrkig=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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