SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b2d7a37836d0868688fe6e00f533781dde408f286a025a5ee6097d795b9d75b' 
  AND token = '8yNkvb003gMY5dTZROVtEk/634ZUB0+hq4G5zDtMwOQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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