SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14b4e3b17b5125576acdfb93eee4bedadc0727992836ac609caedd70b0d771d1' 
  AND token = 'jhKC3vG2F5VAsGBQygL+hWL+ysFOj8cq2OaVrrnbJQk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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