SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e1355e1cfdbd56e43986f6ee0668818d79c0ad9b871e66d18c3d4855501c40a' 
  AND token = 'u08wQscANGU51KPJy9oIu+Ezr3pi0a8wddv411vc6ho=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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