SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2cc251738b56b24527dd0119abeb647db855f42738873459140aa4cdeb8c7c77' 
  AND token = 'uL/h+KppkAFVjU1KmCYZrUs8crufUP5YH+iyvpm1NDM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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