SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '45a9a987bd220495393e57f94225a5f33c563dbf30bbdd406c160688404caca2' 
  AND token = 'gf5260RGj+maeUXiYSeLxQoJx8ANiBQF9zgygShIVis=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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